This is an overview chart. I've plotted all five of the subreddits on one 3D canvas, showing the relationship between the age of the post in days, the rank or position in its subreddit, and the net karma score. You can see that posts on The_Donald don't hang around long before being pushed out by new posts. GoneWild and AskReddit posts have similar trajectories to each other, lasting about twice as long as T_D posts. IAmA and dataisbeautiful, on the other hand, have much longer-lived posts: there's less of a constant stream of new material, so a popular post can be in the top 100 for about 5 days on dataisbeautiful, or up to 8 days for IAmA.